Ubuntu 12.04 and Mint 13 still uses the pae kernel which lets the 32 bit version see all of your ram. Ubuntu 12.10 and Mint 14 doesn't have pae, so they will only see 4gb using the 32 bit version. As of Ub 12.10/Mint 14 you will have to use the 64 bit version to use all 6gb of your ram. The 32 vs 64 editions won't matter as far as the driver goes. Ub 12.04 and Mint 13 are LTS releases. They will be supported for 5 years. 12.10/14 only gets upport for 18 months. That is a personal decision. Personally I like to update to each new release to get newer features. I found a bug report from someone using that driver with connection problems. It may just be the driver stinks. https://bugs.launchpad.net/rt2x00/+bug/1054179
The live CD method would work for 12.04, but a PITA. You would have to have the driver already downloaded and install the "build-essential" package (on the cd) and then compile and load the driver. For 12.10, you would have to do the same and then unload/blacklist the driver that is already running.
"The only thing necessary for the triumph of evil is for good men to do nothing." Edmund Burke